Oil burner control



Dec. 14, 1965 D. R. GRAHL 3,223,137

OIL BURNER CONTROL Filed Jan. 28, 1963 IINVENTOR,

PlE '7 THERMOSTAT W N I 624/44 @WKM United States Patent 3,223,137 OIL BURNER QQNTROL Darwin R. Gran], Lincoln Park, Mich, assignor to American Radiator & Standard Sanitary (Zorporation, New York, N.Y., a corporation of Delaware Filed Jan. 23, 1963, Ser. No. 254,134 4 Claims. (Cl. 158-28) This invention relates to an oil burner control which operates the burner in response to a call for heat by a room thermostat, and which provides a secondary control circuit so that if the burner fails to properly ignite the burner will be de-energized without undergoing additional unsuccessful attempts at ignition. The secondary control circuit is provided with a manual reset means so that after an unsuccessful attempt at ignition manual resetting of the burner control'is required before ignition can again be attempted.

Oil burner controls have in the past included several component devices such as a step down transformer, two or more relays, a manual reset switch, and various flexible lead wires for connecting the components to each other within the control casing. The control casing is usually a relatively small box-like afiair of limited volume, as for example four inches or less on a side. Due to the cramped quarters within such small casing volumes the steps involved in wiring up the control have in the past been tedious, time-consuming, and subject to error.

With the above in mind, it is a principal object of this invention to provide an oil burner control having a reduced number of electrical and mechanical connections within the control casing.

As related to the above, it is a further object to provide an oil burner control which utilizes printed circuits.

A still further object is to provide an oil burner control having a di-electric panel, one face of which accommodates the control components and the other face of which has printed circuitry thereon, the control components having electric terminals projecting through the di-electric panel to soldered connections with the printed circuits, whereby all of the electrical connections can be made on the face of the panel which is unencumbered by the control components.

A further object of the invention is to provide an oil burner control wherein the electrical components are mounted on a di-electric panel by means of spade-like elements which constitute both mechanical mounting devices and electrical connectors, thus enabling the assembler to mechanically mount and electrically connect the components in single step operations.

Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

FIGURE 1 is a top plan view of an oil burner control construction according to my invention;

FIG. 2 is a front elevational view of the FIG. 1 structure, with certain parts thereof broken away for illustration purposes;

FIG. 3 is a right elevational view of the FIG. 1 structure;

FIG. 4 is an enlarged fragmentary sectional view illustrating a connection used in the FIG. 1 embodiment;

FIG. 5 is an enlarged fragmentary sectional view illustrating another connection used in the FIG. 1 embodiment;

FIG. 6 is a fragmentary sectional view taken on line 66 in FIG. 2; and

FIG. 7 is a circuit diagram for the structure of FIG. 1.

Before explaining the present invention in detail it is to be understood that the inventionv is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to FIGS. 1 through 6 of the drawings, there is shown an oil burner control having a dielectric base or panel 10 for mounting a transformer 12, a first relay 14, a second relay 16, and a manual reset switch 18. Each of the transformer, relays 14 and 16, and switch 18 have electrical connector elements which project through slots in panel 10. As best shown in FIG. 4, a representative one of the connector elements comprises a spade-like element 5 having a reduced width section 9 extending beyond the lower surface of panel 10 so as to have a soldered connection 7 with parts of printed circuitry generally designated by numeral 11. Thus, the projecting portions of the connectors are adapted to be soldered directly to the printed circuitry for thereby acting as electrical connectors and also as mechanical mounting devices for the operating components such as the two relays and reset switch.

FIGS. 1 through 3 show a burner control of this invention, while FIG. 7 shows diagrammatically the relation of the control to the other components in an oil burner environment. As shown in FIG. 7, transformer 12 is provided with a primary 24 and a secondary 26. Ter minals T and T on panel 10 are arranged to connect with a room thermostat 27 as is conventional, and terminal T is arranged to be connected with the coil 28 of relay 16, as by means of a printed circuit line 30. The other side of coil 28 connects with a printed circuit line 34 which leads to the terminal 32 of switch 18.

The construction of switch 18 may be varied as to detail, but as shown semi-schematically in FIG. 2 the switch comprises a di-electric case 36 which is provided with the three spade-type terminals 32, 38 and 40. Each terminal may be formed as shown in FIG. 4, whereby the three terminals extend through panel 10 and serve as the sole mounting means for case 36. Terminal 38 is electrically connected with a resistance heater 41 which is wrapped about bimetal 42 and which is adapted to have its lower end electrically connected with terminal 40, not shown in the cutaway portion of FIG. 2. The upper end of the bimetal registers with switch arm 46. The switch arm is floatably positioned on a manually actuable push-button 48, as by means of a compression spring 50.

In operation of switch 18, when heater 41 is energized bimetal 42 slowly warps to the left to disengage detent 44 from switch arm 46 to thereby permit spring 50 to snap arm 46 upwardly out of engagement with terminal 32. This interrupts the circuit between terminals 32 and 40, and prevents arm 46 from moving down toward terminal 32 except after manual depression of button 48. After bimetal 42 has cooled to warp back to its illustrated position pushbutton 48 can be manually depressed to operate arm 46 to the illustrated latched position.

Returning again to FIGS. 1 and 7, terminal 38 is connected with switch terminal 54 of the relay 14 by printed circuit line 56. The cooperating switch terminal 58 of the relay is connected with terminal 59 of the transformer secondary by means of printed circuit lines 60 and 61, and the coil portion 62 of the relay is connected with terminal C by means of a printed circuit line 64. Terminals 54 and 58 form part of a switch designated generally by numeral 57 in FIG. 7.

Terminals C and C are adapted to connect with a flame sensing control device shown diagrammatically in FIG. 7 as a cadmium sulphide cell 66. The connection 3 between terminals C and T is effected through a short printed circuit connector 68, which in the FIG. 1 embodiment is merely a large blob of solder. As shown in FIG. 1, circuit connector 68 is located at one end of a printed circuit line 83 which leads to the terminal 81 on the secondary of the transformer.

Still referring to FIGS. 1 and 7, terminal 40 connects with printed circuit line 72 which leads to a terminal 70 constituting part of the switch portion 77 of the relay 16. The other terminal 74 of this switch portion is connected to terminal 76 of the transformer secondary by means of a printed circuit line 78'.

Relay 16 is provided wtih a second switch 79 having two additional switch terminals numbered 80 and 82. Terminal 82 connects with a short printed line 86 which forms a juncture with an insulated flexible conductor 84. Terminal 82 connects with a printed line 90 which forms a juncture with another flexible insulated conductor 88. Printed circuit line 86 also extends over to the transformer terminal 92. The other terminal 94 of the transformer primary connects with a printed circuit line 96 which connects with the flexible insulated conductor 98.

The control is shown in FIG. 7 in a de-energized condition wherein switches 18 and 57 are closed, and switches 77 and 79 are open; room thermostat 27 is deenergized. On the call for room heat by room thermostat 27 current is supplied from the transformer secondary 26 through a circuit which includes line 83, terminal T room thermostat 27, terminal T line 30, coil 28, line 34, switch 18, heater 41, line 56, switch 57, and lines 60 and 61. As coil 28 is energized it closes switches 77 and 79 so that switch 79 is able to energize the oil burner 91 in the conventional manner. The purpose of switch 77 during this period is to provide a holding circuit for maintaining coil 28 energized even though current should later stop flowing through heater 41 and switch 57.

If the burner is able to successfully ignite, flame responsive switch 66 closes so that a circuit is completed through line 83, terminal T line 68, terminal C switch 66, terminal C line 64, coil 62, and line 61. Coil 62 is thereby energized to open switch 57 and thus prevent heater 41 from opening switch 18. Therefore if a flame is successfully established coil 28 remains energized to complete a circuit through switch 79.

If the burner does not successfully establish or maintain a flame, switch 66 remains in an open condition and no current flows through coil 62. Under this circumstance heater 41 causes birnetal 42 to warp to the left (FIG. 2) for thus opening switch 18. By this action coil 28 is de-energized and switch 79 is thereby opened to thus discontinue current flow to the burner. Failure of the control to establish or maintain a flame causes switch arm 46 to snap upwardly and thus require manual resetting of button 48 to return the switch to its FIG. 2 position.

Referring now to the individual control components, transformer 12 comprises a coil 100 and a laminated rectangular core 102 which is encased in a metal frame 104 of generally U-shaped configuration (as seen in FIG. 2). The frame is of sheet metal construction and has flanges 106 and 108 which overlie the faces of the transformer core. The main wall portion 110 of the frame has spade-like extensions 112 which extend downwardly through slots in panel 10 and which are preferably twisted as shown in FIG. 1 to rigidly retain the transformer assembly on the panel. As best seen in FIG. 3, the terminals for the transformer comprise wire elements 114 which extend downwardly from molded parts of the transformer coil through openings in panel 10 and which are soldered to the printed circuitry in the manner generally shown in FIG. 5.

Referring now to relay 14, said relay includes a rectangular di-electric platform 116 having downwardly extending metal leg elements 118, 54, 120 and 122 at its four corners, Each of the four metal leg elements is provided with a reduced width extension similar to extension 9 shown in FIG. 4, and each of these extensions has solder applied thereto to mechanically and electrically mount the relay on panel 10.

As best shown in FIG. 3, leg 54 is provided with a lateral extension 55 which carries one of the contacts for switch 57. This contact is arranged to be engaged by a contact on the superjacent portion 52 of a resilient L- shaped member 53. The upwardly extending portion of resilient member 53 comprises two spaced strips 49 which are soldered to a metal plate 51 to form an electrical connection therewith. The plate 51 is clamped in place by means of a bracket 45 and screws 47. The lower extremity of bracket 45 extends through panel 10 and forms the aforementioned terminal 58.

Coil portion 62 of relay 14 is energized from terminals which are designated in FIG. 1 by numerals 118 and 122. These terminals take the form of L-shaped metal legs similar in shape to leg 120 shown in FIG. 3. The horizontal portions of these legs connect with lead wires from coil 62, and the lower extremities of these legs project through panel 10 to soldered connections with the printed circuitry as shown generally in FIG. 4. The three legs 54, 118 and 122 serve both as electrical connectors and as mechanical mounting devices for platform 1.16. Leg 120 serves only as a mounting device for the platform.

Coil portion 62 of the relay is disposed within a U- shaped frame comprised of two L-shaped plates 63 and 65 which may be carried jointly by platform 116 and bracket 45'. As shown in FIG. 2, the armature for the relay comprises a plate 43 having a hinged connection with plate 51 and having a fixed connection with the horizontal portion of resilient element 53. Thus the resilient element tends to hold armature 43 in its illustrated lowered position when coil 62 is de-energized. When the coil is energized the armature 43 is drawn upwardly toward core 45 to thus break the circuit between elements 54 and 58.

Relay 16 comprises a U-shaped frame 69 having one flange thereof clamped onto a stack of interposed insulators and conductors by screws 71. Mechanical support for the frame is provided by four stiff metallic spade elements 70, 74, 8t) and 82 (see FIG. 1) which have reduced width extensions projecting through slots in panel 10 so as to have soldered connections with printed circuitry 11 in the manner illustrated in FIG. 4.

The relay further comprises an armature 65' which is pivotally mounted on frame wall 73 and which carries a di-electric plate 67. A transverse slot is provided in plate 67 for accommodating the upper end portions of certain reed-like switch arms, one of which is designated by numeral 75 in FIG. 3. Cooperating with reed 75 is a second reed-like arm 63'. Two other switch arms are disposed behind arms 63, and 75, and are thus not visible in that figure. It will be understood that switch arms 75 and 63' are electrically engaged with spade elements 70 and 74, and that the other two switch arms are electrically engaged with the other two spade elements and 82. Such an arrangement provides the two switches des' ignated by numerals 77 and 79 in FIG. 7.

In operation of relay 16, when coil 28 is de-energized a tension spring 89 holds armature 65 in its illustrated position wherein the two relay switches are open; when coil 28 is energized by terminal members 93 armature 65 is drawn to the right so as to close the two relay switches. The noteworthy feature of relay 16 is that it is mounted on panel 10 solely by means of the four spade elements 70, 74, 80 and 82 which serve additionally as electrical connectors. The relay can be fabricated separately from panel 10 and be installed thereon in a simple one-step operation which does not involve connecting hard-toreach flexible conductors.

The only flexible conductors used in the FIG. 1 construction are conductors 88, 98 and 84. Each of these conductors may be connected into the printed circuitry by having the conductive wire portion 87 thereof extend downwardly through an opening in panel so as to have a soldered connection 95 with the printed circuitry 11. A large opening 97 may be formed in panel 10 to accommodate the three flexible conductors.

Although not shown in the drawing, in practice a rectangular housing may be provided on each face of panel 10 to house the operating components and to isolate the printed circuitry from adjacent structure. The housing for the operating components preferably does not overlie the four terminals C C T and T so that these terminals are freely accessible for connection with the lead wires from thermostat 27 and flame switch 66.

A primary feature of the invention resides in the construction and positional relationship of the four main components 12, 14, 16 and 18 on one face of panel 10, with each of said components having electrical conductor elements extending through openings in the panel to soldered connections with the printed circuitry. In the case of components 14, 16 and 18 the conductor elements are of sufiicient rigidity as to constitute devices for mechanically mounting the components on the panel.

What I claim is as follows:

1. A burner control comprising a step down transformer having a primary circuit connected with the burner and a secondary circuit comprising a room thermostat, a flame-responsive control device, a manual reset switch and heater therefor, a burner-energizer relay, a second relay energized by the flame-responsive control device, and

circuit connections operatively arranged so that initial energization of the room thermostat serves to energize the burner-energizer relay through the reset switch and heater, and establishment of a burner flame causes the second relay to tie-energize the heater without de-energizing the burner-energizer relay or reset switch, and the absence of flame causes the second relay to energize the heater and thereby open the reset switch;

each of said transformer, relays, switches, and heater being disposed on one face of a dielectric panel with terminals thereof projecting through the panel; said terminals being operatively connected by means of printed circuit lines on the other face of the panel; said thermostat and flame-responsive control device being located remote from the panel and being connected into the control circuit by means of terminals mounted on the panel in direct connection with the printed circuit lines.

2. A burner control comprising a step down transformer having a primary circuit and a secondary circuit, a room thermostat, a flame-responsive control device, a reset switch and heater, first and second relays including coils and switches controlled thereby, and circuit connections,

whereby energization of the room thermostat serves to energize the coil of the second relay through the reset switch and heater, and establishment of a burner flame causes the coil of the first relay to open its switch and de-energize the heater, and the absence of flame causes the coil of the first relay to close its switch to energize the heater and thus open the reset switch;

each of said transformer, relay coils, switches, and

heater being disposed on one face of a dielectric panel with terminals thereof projecting through the panel; said terminals being operatively connected by means of printed circuit lines on the other face of the panel; said thermostat and flame responsive control device being located remote from the panel and being connected into the circuit for the burner control by means of terminals mounted on the panel in direct connection with the printed circuit lines.

3. A burner control comprising a step down transformer having a primary circuit and a secondary circuit;

said secondary circuit comprising a first relay coil and a normally closed switch controlled thereby; a flameresponsive control device controlling the flow of current through said first relay coil; a second relay coil having two normally open switches, one of which is arranged to energize the burner and the other of which constitutes a holding switch; a room thermostat arranged to control current flow through the second relay coil; a normally closed reset switch and a heater for opening said reset switch; said heater and reset switch being in series with one another, and said heater and holding switch being in parallel with one another;

whereby energization of the room thermostat serves to energize the second relay coil through the reset switch and heater, and establishment of a burner flame causes the first relay coil to open its switch and thus de-energize the heater, and the absence of flame causes the first relay coil to close its switch to energize the heater and thus open the reset switch;

each of said transformer, relay coils, switches, and heater being disposed on one face of a dielectric panel with terminals thereof projecting through the panel; said terminals being operatively connected by means of printed circuit lines on the other face of the panel; said thermostat and flame responsive control device being located remote from the panel and being connected into the control circuit by means of terminals mounted on the panel in direct connection with the printed circuit lines.

4. A burner control comprising a step down transformer having a primary circuit and a secondary circuit;

said secondary circuit comprising a winding having two end taps and an intermediate tap, a first control circuit connecting said end taps which includes a normally open flame responsive control device and a first relay coil; a second control circuit connecting one of the end taps and said intermediate tap comprising a room thermostat, a second relay coil, a normally closed reset switch, and a normally open holdng switch controlled by the second relay coil; a third control circuit interconnecting the first and second control circuits comprising a heater for the reset switch and a normally closed switch controlled by the first relay coil;

the transformer primary circuit including a normally open burner-energizer switch controlled by the second relay coil;

whereby energization of the room thermostat serves to energize the second relay coil through the reset switch and heater, and establishment of a burner flame energizes the first relay coil to open its switch and thus de-energize the heater, and the absence of flame de-energizes the first relay coil to close its switch and energize the heater for thus opening the reset switch;

each of said transformer, relay coils, switches, and heater being disposed on one face of a dielectrc panel with terminals thereof projecting through the panel; said terminals being operatively connected by means of printed circuit lines on the other face of the panel; said thermostat and flame responsive control device being located remote from the panel and being connected into the control circuits by means of four terminals mounted on the panel in direct connection with the printed circuit lines.

References Cited by the Examiner UNITED STATES PATENTS 2,567,807 9/1951 Edelman 158-28 2,743,768 5/1956 Schell 15828 2,835,321 5/1958 Delancey 1582 2,898,518 8/1959 Lynn 317101 3,060,997 10/1962 Maney 158-28 FREDERICK L. MATTESON, JR., Primary Examiner. JAMES W. WESTHAVER, Examiner. 

1. A BURNER CONTROL COMPRISING A STEP DOWN TRANSFORMER HAVING A PRIMARY CIRCUIT CONNECTED WITH THE BURNER AND A SECONDARY CIRCUIT COMPRISING A ROOM THERMOSTAT, A FLAME-RESPONSIVE CONTROL DEVICE, A MANUAL RESET SWITCH AND HEATER THEREFOR, A BURNER-ENERGIZED RELAY, A SECOND RELAY ENERGIZED BY THE FLAME-RESPONSIVE CONTROL DEVICE, AND CIRCUIT CONENCTIONS OPERATIVELY ARRANGED SO THAT INITIAL ENERGIZATION OF THE ROOM THERMOSTAT SERVES TO ENERGIZE THE BURNER-ENERGIZER RELAY THROUGH THE RESET SWITCH AND HEATER, AND ESTABLISHMENT OF A BURNER FLAME CAUSES THE SECOND RELAY TO DE-ENERGIZE THE HEATER WITHOUT DE-ENERGIZING THE BURNER-ENERGIZER RELAY OR RESET SWITCH, AND THE ABSENCE OF FLAME CAUSES THE SECOND RELAY TO ENERGIZE THE HEATER AND THEREBY OPEN THE RESET SWITCH; EACH OF SAID TRANSFORMER, RELAYS, SWITCHES, AND HEATER BEING DISPOSED ON ONE FACE OF A DIELECTRIC PANEL WITH TERMINALS THEREOF PROJECTING CONNECTED BY MEANS OF TERMINALS BEING OPERATIVELY CONNECTED BY MEANS OF PRINTED CIRCUIT LINES ON THE OTHER FACE OF THE PANEL; SAID THERMOSTAT AND FLAME-RESPONSIVE CONTROL DEVICE BEING LOCATED REMOTE FROM THE PANEL AND BEING CONNECTED INTO THE CONTROL CIRCUIT BY MEANS OF TERMINALS MOUTED ON THE PANEL IN DIRECT CONNECTION WITH THE PRINTED CIRCUIT LINES. 